聚多巴胺磁分子印迹材料制备及其在食用油中黄曲霉毒素B富集中的应用

目的 建立了聚多巴胺磁性分子印迹聚合物 用于食用油中黄曲霉毒素B的吸附富集方法。方法 以多巴胺为功能单体和交联剂，5,7-二甲氧基香豆素为模拟模板分子，一步法在Fe3O4 NPs表面制备磁分子印迹聚合物。采用透射电子显微镜和红外光谱仪对该分子印迹材料形态和结构进行表征，研究了其对两种黄曲霉毒素B吸附性能。最终以该印迹材料作为分散固相萃取剂，对影响黄曲霉毒素B吸附的条件进行了优化。结果 该分子印迹材料对两种黄曲霉毒素B的吸附模式符合Langmuir理论，对黄曲霉毒素B1和黄曲霉毒素B2最大吸附容量分别为0.46 mg/g和0.047 mg/g。在最佳萃取条件（材料用量（10 mg）、溶液pH（7.0）、超声时间（5 min）和1 mL（解吸2次，每次0.5 mL）3%乙酸/乙腈作为解析液下，结合配有大体积流通池的超高效液相色谱-荧光检测法定量检测，黄曲霉毒素B1和黄曲霉毒素B2浓度分别在0.005-0.500 ng/mL（R=0.9989）和0.001-0.100 ng/mL（R=0.9992）范围内与对应的峰面积呈现良好的线性相关性，检出限分别为0.0024 ng/mL和0.00038 ng/mL，食用油样品加标回收率为93.2%~104.0%，相对标准偏差5.8%~7.7%，且可重复使用至少7次。结论 该吸附富集方法具有快速、低廉、选择性高、稳定性好等特点，适用于食用油中黄曲霉毒素B的前处理。

Preparation of polydopamine magnetic molecularly imprinted polymers for enrichment of aflatoxin B in edible oil

Objective To develop a method for the extraction and enrichment of aflatoxin B in edible oil by the specific magnetic molecularly imprinted polymers (MIPs). Methods Using dopamine as a functional monomer and cross-linker, and 5, 7-dimethoxycoumarin as the dummy template, the MIPs were fabricated on the surface of ferroferric oxide nanoparticles by a one-pot method. The prepared MIPs were characterized through a transmission electron microscopy and a fourier transform infrared spectrometer. The adsorption properties towards two aflatoxin B were studied. The MIPs were used as a sorbent for dispersive solid-phase extraction, the extraction conditions were optimized. Results The adsorption properties of MIPs to two aflatoxin B matched the Langmuir isotherm model, and the maximum adsorption capacities were 0.46 mg/g for AFB1 and 0.047 mg/g for AFB2. Under optimized conditions including MIPs amount (10 mg), pH value 7.0, equilibrium time (5 min), and 1 mL (eluted twice, each 0.5 mL) 3% acetic acid/acetonitrile as desorption solvent, combined with UPLC-FLD with a large volume flow cell, the calibration plots are linear in the range of 0.005-0.500 ng/mL (R=0.9989) and 0.001-0.100 ng/mL (R=0.9992) with LODs of 0.0024 ng/mL and 0.00038 ng/mL for aflatoxin B1 and aflatoxin B2, respectively. The recoveries from spiked edible oil sample are 93.2% - 104.0% with RSDs of 5.8-7.7%. And the MIPs were reused for 7 cycles. Conclusion The proposed method is rapid, cheap, high selectivity and stability for extraction and recognition of aflatoxin B1 and aflatoxin B2 in edible oil.